Characteristics of CTX-M Type Extended Spectrum beta-lactamase Producing Non-typhoi dal Salmonella Isolates / 감염과화학요법

ABSTRACT

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing Salmonella have been increasingly reported worldwide. ESBL-producing Salmonella is of particular concern since children cannot be treated with quinolones. This study was conducted to determine the phenotypic and genetic characteristics of ESBL-producing Salmonella in a tertiary hospital. MATERIALS AND METHODS: Four clinical ESBL-producing isolates of non-typhoidal Salmonella were collected during 2001 to 2009. Antimicrobial susceptibility was determined by disk diffusion test and VITEK-II system. ESBL production was tested by ESBL phenotypic confirmatory test. TEM, SHV, CTX-M1, CTX-M2, CTX-M8, and CTX-M9 type ESBL genes were detected by PCR amplification, and PCR products were subjected to direct sequencing. RESULTS: Phenotypic confirmatory test showed that 4 of the 300 non-typhoidal Salmonella isolates were ESBL-producing 3 S. Enteritidis and 1 S. Typhimurium. All 4 isolates were recovered during the past 1 year period. All 3 S. Enteritidis harbored CTX-M-15, while the S. Typhimurium harbored CTX-M-14. All CTX-M-15-producing S. Enteritidis isolates showed resistance both to cefotaxime and ceftazidime, while the CTX-M-14-producing S. Enteritidis were resistant only to cefotaxime. CONCLUSIONS: ESBL-producing nontyphoidal Salmonella has emerged recently and the type of ESBL has switched from TEM and SHV to CTX-M.